Phases of Matter

How much energy is needed to vaporize 75.0 g of diethyl ether (C4H10O) at its boiling point (34.6°C), given that ΔHvap of diethyl ether = 26.5 kJ/mol?

26.8 kJ

How much energy is needed to vaporize 25.0 g of H2O at 100°C, given that ΔHvap of water = 40.7 kJ/mol?

56.5 kJ

The vapor pressure of dichloromethane at 260 K is 71 torr. What is the vapor pressure at 310 K, given that ΔHvap = 31.4 kJ/mol?

737 torr

How much energy is required to take a 15.0 g sample of ice at −15.0°C to liquid water at 45.0°C? Ice warming Cs = 2.09 J/g∙°C Enthalpy of fusion ∆H = 6.02 kJ/mol Liquid water warming Cs = 4.18 J/g∙°C Enthalpy of vaporization ∆H = 40.7 kJ/mol Steam Warming Cs = 2.01 J/g∙°C

8.30 kJ

What type of phase change occurs going from B to A on the phase diagram?

Freezing

What type of phase change occurs going from A to B on the phase diagram?

Fusion

What phase change is known as condensation?

Gas to liquid

What phase change is known as deposition?

Gas to solid

What phase is present at point A on the phase diagram?

Solid

What phase change is known as sublimation?

Solid to gas

What phase change is known as fusion?

Solid to liquid

What type of phase change occurs going from A to C on the phase diagram?

Sublimation

What is the critical point?

The point beyond which the liquid and gas phases coexist

Which statement is true about the relationship between intermolecular forces and the boiling point of a liquid?

The stronger the intermolecular forces, the higher the boiling point.

What type of phase change occurs going from B to D on the phase diagram?

Vaporization

Select the true statement regarding vapor pressure. As the temperature of a sample increases, the vapor pressure decreases. The vapor pressure of all samples is zero until the temperature reaches the boiling point. As the temperature of a sample increases, the vapor pressure increases. The vapor pressure of all substances is the same at a given temperature.

As the temperature of a sample increases, the vapor pressure increases.

What type of phase change occurs going from D to B on the phase diagram?

Condensation

What type of phase change occurs going from C to A on the phase diagram?

Deposition

What phase is present at point B on the phase diagram?

Liquid

What phase change is known as vaporization?

Liquid to gas

What phase change is known as freezing?

Liquid to solid

Select the true statement about boiling point. The boiling point of water is always 100°C, regardless of the atmospheric pressure. As the atmospheric pressure increases, the boiling point decreases. The boiling point is the temperature at which the vapor pressure equals the atmospheric pressure. The boiling point is unrelated to the atmospheric pressure.

The boiling point is the temperature at which the vapor pressure equals the atmospheric pressure.